Wyniki wyszukiwania - Biblioteka Nauki

1

Influence of the vacuum-arc source configuration and arc discharge parameters on the evolution and location of arc spots on the cathode surface

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Walkowicz J. , Smolik J. , Słomka Z. , Kułakowska-Pawlak B. , Żyrnicki W.

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2009

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tom Vol. 37, nr 2

719-725

EN

Purpose: The paper presents investigations of the evolution, structure and location of arc spots on the cathode frontal surfaces of two types of industrial arc sources. Design/methodology/approach: The temporal behaviour of cathode spots was recorded with the use of a fast CCD camera. The experiments were performed at four values of arc current, nine compositions of the process atmosphere N2+C2H2 and three pressure ranges of the process atmosphere. Findings: The analysis of the recorded pictures revealed the fine structure of the arc discharge for the investigated range of process conditions. Both temporal and spatial behaviour of cathode spots were different for both investigated arc sources. The correspondence between radial distributions of the cathode spots on the cathode surface and radial distribution of plasma flow elements analysed in the volume of the vacuum chamber was revealed. Research limitations/implications: The paper show experimental methodology that can be used for the research of the specificity of cathode spots movement on the cathodes made from different materials. Originality/value: The originality of the research presented in the paper consists in assigning overall correlation between vacuum-arc source configuration and parameters of vacuum-arc discharge – on the one hand, and space-time behaviour of the arc spots during their movement on the circular cathode surface and radial distribution of excited and ionized atoms of the cathode material in the deposition chamber – on the other.

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Structure and mechanical properties of PVD gradient coatings deposited onto tool steels and sialon tool ceramics

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Dobrzański L. A. , Staszuk M. , Křiž A. , Lukaszkowicz K.

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2009

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tom Vol. 37, nr 1

36-43

EN

Purpose: The paper presents investigation results of the structure and mechanical properties of gradient coatings deposited by cathodic arc evaporation - physical vapour deposition (CAE-PVD) techniques onto the X40CrMoV5-1 hot work tool steel, HS6-5-2 high speed steel and SiAlON tool ceramics. The Ti(C,N), (Ti,Al)N and (Al,Si,Cr) N coatings were investigated. Design/methodology/approach: Microstructure was characterised using scanning and transmission electron microscopy. The phase composition of the investigated coatings was determined by means of the X-ray diffractometer. The chemical concentration changes of the coating components, and the substrate material were evaluated in virtue of tests carried out in the GDOS spectrometer. Tests of the coatings’ adhesion to the substrate material were made using the scratch test method. Findings: It was found out that the structure of the PVD coatings deposited onto all substrates is composed of fine crystallites. The investigations made by use of the glow discharge optical emission spectrometer indicate to the existence of the transition zone between the substrate material and the coating. The results show that all coatings present good adhesion. The critical load LC2, which is in the range 35-90 N, depends on the coating type and substrate. Good adhesion of the coatings deposited to the substrate should be connected with the existence of the transition zone. All the coatings are demonstrated by high hardness. Research limitations/implications: Ti(C,N), (Ti,Al)N and (Al,Si,Cr) N gradient coatings can be applied for cutting tools and hot working tools. Originality/value: Working out and testing PVD coatings obtained by tool ceramic and tool steels is a special future of development direction in a domain of thin coatings.

3

Plasma modification of medical implants by carbon coatings depositions

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Grabarczyk J. , Kotela I.

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2009

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tom Vol. 37, nr 2

277-281

EN

Purpose: The main goal was to work out the technology of deposition of carbon layers onto surface of medical implants made of the AISI316L medical steel. So far the results of carried investigations have proved that layers synthesized in RF PACVD process noticeably improve the biotolerance of the medical steel. Positive experimental results concerning the implementation of carbon layers conducted in the Institute of Materials Science and Engineering of the Technical University of Lodz were the basis for attempt of industrial application of the worked out technology. Design/methodology/approach: Carbon layers were manufactured using radio frequency plasma RF PACVD method. The technology was worked out for the surfaces of the intramedullary nails. The investigations were carried out in order to compare obtained synthesis results with the layers deposited under the laboratory conditions. In this work the following are presented: the surface topography investigation, results of nanohardness and adhesion measurements as well as the raman spectra. Medical examination results were presented in our earlier publications. In the description of obtained investigation results are also presented the preliminary results of the medical treatment effects with the use of intramedullary nails covered with the carbon layer. Findings: Carbon layers manufactured onto intramedullary nails presented good mechanical properties. Applied synthesis parameters made it possible to manufacture uniform film onto whole implant surface. Thickness of the layer was varied in the range of 200 – 400 nm, however total modification area contained 3.5 micrometers. Nails covered with the carbon layer positively passed the tests and were admitted into medical trade turnover. Positive medical treatment results were observed especially in case of patients with affirmed allergies onto alloying components contained in medical steels like chromium and nickel. Research limitations/implications: Significant matter for the examinations had the introduction of the additional control parameters of the plasmo-chemical layers synthesis process. From the point of view of the industrial implementation of technology the fact of limited process efficiency can be. Originality/value: The fundamental value of conducted investigations is the industrial application of the technology of deposition of carbon layers onto intramedullary nails. Currently those products are available in the business offer of MEDGAL Company.

4

Correlation between spatial distribution of the components of reactive plasma flow and the stoichiometry and defectiveness of deposited coatings

80%

Walkowicz J. , Smolik J. , Brudnias R. , Kułakowska-Pawlak B. , Żyrnicki W.

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2009

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tom Vol. 37, nr 2

712-718

EN

Purpose: The subject of the presented research was reactive plasma generated by circular vacuum-arc sources used for deposition of thin hard coatings. Design/methodology/approach: Experimental investigations on spatial distribution of ionized and excited plasma components were performed with the use of the optical emission spectroscopy. Quantitative analysis of microdroplets distribution was carried out using measuring optical microscope supplied with the numerical image analysis system. Findings: Based on the obtained radial distributions of volatile and condensed components the general picture of plasma flow emitted by a single circular arc source was reconstructed. Radial distributions of analysed emitting elements and analysed fractions of microdroplets showed layered structures that depended on the discharge conditions. Research limitations/implications: The spectral method used for the reconstruction of concentration distributions of ionised and excited plasma components generated by a single circular arc source could not be used for reconstruction of such distributions in the vacuum chamber of the industrial device. Originality/value: The carried out investigations showed that the differences in spatial distributions of plasma active elements determine the uniformity of crystallization conditions in vacuum-arc deposition processes performed in large-scale multi-source industrial devices.

5

Optical properties and morphology of PECVD deposited titanium dioxide films

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Kowalski J. , Sobczyk-Guzenda A. , Szymanowski H. , Gazicki-Lipman M.

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2009

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tom Vol. 37, nr 2

298-303

EN

Purpose: The purpose of the present work is to compare the structure and optical properties, with respect to their potential optical applications, of titanium dioxide films synthesized with the PECVD method from two different precursor materials, namely titanium tetrachloride and titanium tetraethoxide (TEOT). Design/methodology/approach: Optical properties as well as thickness of the films were analyzed by means of Variable Angle Spectroscopic Ellipsometry (VASE). Morphology studies were carried out by Scanning Electron Microscopy (SEM) and chemical composition characterisation was performed with the help of Energy Dispersive Spectroscopy (EDS) unit coupled with the electron microscope. Findings: Optical parameters approaching those of titanium dioxide were achieved for both precursors. Studies of morphology show that the films produced from TEOT have favourable, smooth surface in contradiction to broccoli-like structure obtained for the chloride precursor. The type of substance used for titanium oxides synthesis determined chemical composition of the films resulting in their enrichment with either chlorine or carbon, depending on the precursor composition. Practical implications: The optical quality of the films is good enough to suggest their applications in stack multilayer interference filters. The refractive index values of these films advocate their use as high refractive index materials while their low extinction coefficients assure the devices transparency. Originality/value: The work presents deposition rates as well as the films optical properties, chemical composition and morphology in relation to operational parameters of their synthesis. It also provides a comparison of these characteristics for two competitive precursor compounds. Finally, it presents the capability of PECVD method for the deposition of optical coatings onto polymer substrates.

6

Predicting properties of PVD and CVD coatings based on fractal quantities describing their surface

70%

Kwaśny W.

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2009

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tom Vol. 37, nr 2

125-192

EN

Purpose: The goal of the presented study was to develop a methodology giving a possibility to predict functional properties of coatings obtained in the PVD and CVD processes on tool materials, based on fractal- and multi-fractal quantities describing their surface. Design/methodology/approach: Effect of process type and deposition conditions on structure and shape of surface, as well as mechanical and service properties of the obtained coatings were determined. Methodology and detailed description of coatings topography obtained in PVD and CVD process on tool materials, including use of the fractal- and multi-fractal geometry based on images obtained on the atomic forces microscope were worked out. Relationships between fractal- and multi-fractal quantities and their mechanical and service properties were determined. Findings: The investigation results confirmed the feasibility to predict hardness and erosion resistance of coatings obtained in the magnetron PVD process, as well as the service properties defined in the cutting ability test for coatings obtained in the arc PVD process and in the high-temperature CVD process, based on the surface fractal dimension Ds value for their surface topography. Practical implications: Determining significant quantitative correlations between fractal quantities defining coatings’ surfaces, as well as their service and/or mechanical properties provides the opportunity to predict their end-user properties. Originality/value: Fractal analysis was applied for characterization of PVD and CVD coatings surfaces.